D31. Localized Dermal Backflow on ICG Lymphography in Female Breast Cancer Survivors Without Breast Cancer-Related Lymphedema After Axillary Lymph Node Dissection

PURPOSE: Variations of upper extremity lymphatic anatomy may protect women from the development of breast cancer-related lymphedema (BCRL) after axillary lymph node dissection (ALND). We mapped upper extremity lymphatic anatomy with indocyanine green (ICG) lymphography in volunteer female breast cancer survivors without a history of BCRL diagnosis. METHODS: Female breast cancer survivors treated with ALND (≥10 lymph nodes removed) at least two years prior were recruited. Volunteers underwent SPECT/CT lymphoscintigraphy, limb volume measurements, and bioimpedance spectroscopy to rule out the presence of BCRL. Bilateral ICG lymphography was performed using a standardized protocol. RESULTS: Twenty volunteers excluded from BCRL diagnosis completed the study at a median of 11.2 years after ALND. Dermal backflow was observed in 70% (14/20) of affected arms and no contralateral, unaffected arms. Dermal backflow appeared in the antecubital fossa in 78% (11/14) of volunteers with nonlinear ICG findings. CONCLUSION: Dermal backflow in the antecubital fossa was observed in over half of female breast cancer survivors without BCRL at a median of 11.2 years after ALND. Dermal backflow in the antecubital fossa may represent drainage to epitrochlear lymph nodes and perforating lymphatic vessels, a superficial to deep pathway demonstrated in cadaveric dissections. Dermal backflow in the absence of BCRL expands the spectrum of normal lymphatic function and may represent collateralization rather than disease.